In the hours after the suspected Brooklyn subway station gunman was arrested, police got a tip that raises a new question in the investigation: Did the alleged shooter do a possible test run at a Brooklyn airfield leading up to the attack?
Three law enforcement sources told NBC New York that members of the Joint Terrorism Task Force and the NYPD Crime Scene unit were at Floyd Bennett Field near Jamaica Bay Wednesday evening, recovering remnants of smoke grenades.
A tipster said that a white van — possibly a U-Haul van — was seen in the area in the very early morning hours Tuesday, according to law enforcement sources, and police were told someone may have been exploding smoke grenades near a wooded area.
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Investigators stressed that it was far too soon to determine if there could be any connection to the subway attack suspect, and if it was any sort of possible test run of the smoke grenades. Nevertheless, officials are investigating to see if any connections could be made.
Law enforcement will look to see if that U-Haul van could be the same one that helped police link the shooting at the Sunset Park subway station to Frank James, the 62-year-old who was taken into custody in the East Village around 1:45 p.m. Wednesday without incident after a 28-hour manhunt, police said.
Law enforcement had zeroed in on James in the hours after Tuesday's shooting on the train at the 36th Street station, lifting critical clues from a rented U-Haul van, surveillance footage and evidence at the scene, including a gun, hatchet, additional ammunition and a bag that had unused smoke canister and fireworks.
Police said a Crime Stoppers tip on Wednesday helped nab the alleged shooter — and law enforcement sources said they believe James called the tip line himself, saying he was at a McDonald's on the Lower East Side.
"This is Frank. You guys are looking for me ... my phone is about to die," the sources say the caller said.
James wasn't at the McDonald's by the time cops responded to the call, but they drove around and eventually spotted him on a street corner. He didn't resist.
Three sources familiar with the arrest said one of the NYPD officers approached and asked the man if he was James. He responded saying yes, and that he had been waiting for police to find him all day, according to the sources.
The suspect was questioned at the 9th Precinct Wednesday afternoon, before being led out of the stationhouse in handcuffs. A federal complaint in Brooklyn charged him with one count of committing a violent attack with a dangerous weapon on mass transportation, with the intent to cause death and serious bodily injury to New York City transit riders, authorities said.
Prosecutors said they also intend to prove he crossed state lines to commit the attack, and pledged justice would be served. A conviction carries a max sentence of 20 years in prison.
James didn’t respond to reporters’ shouted questions as he was led to a police car Wednesday afternoon. He was transferred hours later to federal Bureau of Prisons custody and was being held at the Metropolitan Detention Center in Brooklyn.
The first court appearance is set for Thursday. Once in police custody, James refused to answer any questions, and asked for a lawyer.
Just ahead of the arrest, law enforcement sources said a MetroCard purchased with a credit card linked to James was swiped at a Brooklyn subway station Tuesday night, hours after the attack.
Investigators believe James may still have been riding the subways following the shooting. MetroCard data isn't real-time, though, and his travel direction wasn't clear, they said. James' last known whereabouts were traced to Park Slope's Ninth Street and Seventh Avenue subway station, which he was seen entering around 9:15 a.m. Tuesday, less than an hour after the shooting, NYPD Chief of Detectives James Essig said.
It wasn't immediately clear what James was doing in the time between that Park Slope sighting and his capture in Manhattan on Wednesday.
Other surveillance video was clear -- and apparently showed James entering the Kings Highway N station, not far from where the U-Haul was found, about two hours before he allegedly opened fire on commuters roughly eight stops away.
Essig said the same black rolling suitcase James is seen taking into the Kings Highway station, three blocks from where the U-Haul was left, was recovered at the 36th Street shooting scene. The construction vest and helmet James was seen wearing in that video also were recovered nearby in a trash bin, Essig added.
How James escaped the chaotic scene at 36th Street had remained unclear until Wednesday, when top NYPD officials explained how they think, after firing 33 shots, he got out as emergency personnel raced to treat the wounded.
According to the preliminary investigation, James hopped on an R train that had pulled into 36th Street and took it one stop to 25th Street, where he was also seen on surveillance cameras, Essig said. The handgun recovered at the shooting scene was also traced to the suspect. It appears he purchased it in Ohio in 2011.
Law enforcement officials believe the attack that injured at least 23 people, 10 of them by gunfire and some of them children, was premeditated. The fact alone jarred riders already skittish amid recent upticks in subway violence and once again interrupted New York City's rocky pandemic recovery.
Five of the gunshot victims were critically injured, with details on the nature of their wounds not immediately clear. No fatalities were reported.
One source close to the investigation says the gunman's weapon may have jammed, potentially preventing further tragedy.
The gun was recovered at the scene, as was a bag with smoke canisters and fireworks, along with a hatchet, a spray bottle of gasoline and a fuse — lending further credence to the theory of a premeditated attack on New York City transit riders.
Three extended magazines of ammunition were also recovered at the scene: one still in the handgun, one in a backpack and one under his subway seat. The federal Bureau of Alcohol, Tobacco, Firearms and Explosives completed an urgent trace to identify the gun’s manufacturer, seller and initial owner. That came back to James.
An MTA surveillance camera in the station wasn't working at the time of the shooting, three sources say. It's not clear why, but officials say there were “a lot of different options” from cameras elsewhere on the subway line to get a glimpse of the shooter.
More than a dozen victims who weren't hit by gunfire were injured in the crowd response to the chaos, officials said, with injuries including smoke inhalation, panic attacks and falling. Some of the wounded were in the same train car as the suspect, while others were on the platform, authorities said.
All of the victims are expected to survive.